If there was a simple and patriotic answer, I would strongly recommend local hosting. That would be like asking if I preferred that production of all goods (and services) be done locally.
Lets take a scenerio where all hosting is done locally. Aside from the heavy Facebook activity, a lot of internet traffic would be local and we (read ISPs) would not be dependant on expensive international traffic. The result we'd expect is reduced cost on internet connections. Some ISPs would even dare to offer free connections on local traffic and charge you only for international traffic. Great stuff, right?
So what's the comparison between local hosting and international hosting? Well, my pocket doesn't feel patriotic enough. For starters, most hosting companies with the servers in Kenya are expensive. There are some exceptions like Safaricom whose pricing is very competitive by any standards. I shall not list Jambo Telkom as an exception because their website and service do not shine too well for them.
Maybe cost is not an issue for you and what you want to a good product. Well, once again, most Kenyan hosting comes with the very basic tools where the web developer may have quite a task. (If my clients host with some ISPs I charge extra for the headache I'll have to go through). The standard web hosting package should allow a curious, non-techy client find their way around and see many easy to use tools.
What about space? Its a shame to see ISPs counting their web space by MB's when they should be moving from GB to unlimited space like 'everyone' else.
Once you've signed up for any web hosting, you shall need support. This is with setting up email accounts or website uploads and when there is server downtime, you need someone to explain what is happening. If the server is not set up for dummies, there are bound to be more need for customer care. As much as this is an area that would give local hosting a +1, it doesn't, most support is a headache. Here's where opportunists (like myself) take advantage. Get a big chunk of space on an international server, sub-divide the space and sell it locally. Reseller hosting (that's what its called) gives the client a great package with local support. At the end of the day, reseller hosting of this kind is not local hosting.
So back to the question, "should your web hosting be local or international?" Here's my answer: If someone can recommend to you a good local host, go with it. I recently uploaded a website on a Wananchi server and the set up was good. I don't have any experience with Safaricom hosting, but I think it would be worth the consideration.